This invention relates to plain paper electrostatographic copying, and more specifically, to a method of treating paper used in this process to enhance the adhesion of toner thereto.
The art of electrostatographic copying involves the use of a photoconductive element or plate which is uniformly electrostatically charged in order to sensitize its surface. The plate is then exposed in an imagewise manner to activating electromagnetic radiation which selectively dissipates the charge in the exposed areas of the photoconductive material while leaving behind a latent electrostatic image in the non-exposed areas. This latent, electrostatic image may then be developed by depositing a finely divided electroscopic marking material known as toner on the surface of the photoconductive plate. Transfer of the toner from the plate to a receiving member such as plain paper, with subsequent thermal fusing of the toner into the paper, results in a permanent copy.
One method of fusing the toner particles into the paper is known as roll fusing wherein the paper is contacted under pressure with a heated fuser roll. Roll fusing, as contrasted with radiant fusing, has the advantages of lower power requirements, faster output and the ability to fuse both sides of the paper which is essential when copying in the duplex mode.
It is preferred to keep the temperature of the heated roller as low as possible in order to keep problems such as scorching, paper curl, etc. associated with high roller temperatures to a minimum. Of course, the roller temperature must not be reduced to such a low level that the fusing efficiency is affected. Accordingly, it would be desirable and it is an object of the present invention to improve the efficiency of the aforementioned fusing operation to thereby permit efficient fusing at reduced temperatures.